1. Field of the Invention
This invention relates, generally, to refresbable Braille display systems for use as monitors in computer systems and, more particularly, to refreshable Braille display systems using microelectromechanical (MEMS) actuators.
2. Description of the Related Art
The flourishing computer and information revolution has left behind visually impaired and particularly visually and hearing impaired individuals. This is due to the fact that visual display units, typically cathode ray tubes (CRTs), are the heart of all modern communication and information systems including the Internet. This especially affects those impaired individuals in the technical fields. To remedy this situation and promote the mandates of the Americans with Disabilities Act that mandates equal access and opportunities be presented to all capable individuals, Congress has proposed a State Model Bill. The bill would provide materials in a computer-accessible format capable of Braille reproduction. It states, xe2x80x9cthe Legislature finds that:
(1) the advent of the information age throughout the United States and around the world has resulted in lasting changes in information technology;
(2) use of interactive visual display terminals by state and state-assisted organizations is becoming a widespread means of access for employees and the public to obtain information available electronically, but nonvisual access, whether by speech, Braille, or other appropriate means has been overlooked in purchasing and deploying the latest information technology;
(3) presentation of electronic data solely in a visual format is a barrier to access by individuals who are blind or visually impaired, preventing them from participating on equal terms in crucial areas of life, such as education and employment;
(4) alternatives, including both software and hardware adaptations, have been created so that interactive control of computers and use of the information presented is possible by both visual and nonvisual means; and
(5) the goals of the state in obtaining and deploying the most advanced forms of information technology properly include universal access so that segments of society with particular needs (including individuals unable to use visual displays) will not be left out of the information age.xe2x80x9d
Prior art computer interfaced Braille devices use various mechanisms to actuate the Braille dots and xe2x80x9crefreshxe2x80x9d the text. The dots are controlled via macroscopic actuators comprised of piezoelectric materials, shape memory alloys, and solenoids to raise individual pins in the Braille characters. Most of these devices display one or two lines and up to 80 Braille characters per row. Ideally, more rows of Braille text are desired, however, the complexity of the actuators and the close spacing of the Braille dots limit the number of Braille characters. Such actuators also require a very large xe2x80x9cvolume overheadxe2x80x9d to accommodate this complex network of actuators and wires needed to operate the Braille dots. The result is that the foot print of the unit is much larger than the display surface and it is difficult to skin information based on the limited number of Braille characters.
Recently, a company in Cambridge Mass. called Braille Displays overcame the limitation of two rows of Braille cells. This company with the support of the National Science Foundation was able to produce a prototype 4 line by 40 column prototype refreshable Braille display. This 160 cell display is not commercially available. Telesensory produces an 80 character unit, PowerBraille 80 (PB80). This device has many user friendly features integrated into its device such as a cursor locator, a touch sensitive strip and scrolling toggle.
U.S. Pat. No. 5,685,721, to Decker, discloses a macro-sized shape-memory alloy based actuator enclosed in a series of tubes and housed in modules which are mounted into a multi-row display under ledges. U.S. Pat. No. 5,766,013, to Vuyk, discloses another macro-sized actuation technique utilizing an intrinsically conducting polymer sheet that expands when a charge is applied. Another macro-sized actuation technique, utilizing a rotary actuator with cams is disclosed by U.S. Pat. No. 5,453,012, to Hudecek. Also, Garner, U.S. Pat. No. 5,496,174 utilizes an electrorheological fluid that expands when a high voltage is applied. All of these devices suffer from the same fundamental problems: a large number of individual components needed for each Braille dot increasing assembly problems; high power requirements eliminating the potential for portability and creating problems dissipating the excess heat; responding fast enough to allow refresh rates appropriate for computer based communications; and, the difficulties in assembling the large number of Braille dots needed for true replication of computer display terminals.
Another approach to providing access to the visually impaired has been the development of optical recognition systems attached to voice synthesizers. Although these devices represent an enormous leap forward in access to both computerized and printed material, they are not appropriate for all tasks. Specifically, they cannot be used with detailed technical material which has a very specialized vocabulary. Medicine, law, accounting, engineering, and science careers are restricted by this limitation. Voice Synthesizing devices are not effective at dealing with tabular material. The voice synthesizing devices do not provide blind accountants and bookkeepers the access they require to spreadsheets and databases. Furthermore, voice synthesizers are not capable of limited document skimming, or provide a means to address accessing links otherwise known as sub-directories or complementary subject indicators. Perhaps most important, these reading devices provide limited ability to edit text or tables.
The devices currently available for the sight impaired are limited and have drawbacks in that they do not have fast enough refresh rate or sufficient Braille character ability to replicate a computer display, including memory capacity, readable area, and scanning and highlighting functions; are bulky and heavy; can not be adapted for different applications, i.e., a lap top vs. a desk top computer; and cannot xe2x80x9cdisplayxe2x80x9d technical, accounting, spreadsheets, or other specialized forms of display which are not a basic textual document.
Accordingly, a need exists for a refreshable Braille display that overcomes the above mentioned limitations and drawbacks.
The present invention provides a device to satisfy the aforementioned need.
One object of the present invention is to provide a Braille display system which has a rapid refresh rate of the Braille dots.
Another object of the present invention is to provide a refreshable Braille display system that has the ability to conveniently present text, spreadsheet and database information, technical material and information in tabular or columnar format to visually impaired persons.
Still another object of the present invention is to provide a refreshable Braille display that allows a user to access links or subdirectories without removing their hands from the display surface.
Still another object of the present invention is to provide a modular Braille display system that is flexible so that it can be sized and arranged to fit a user""s needs.
Still another object of the present invention is to provide a Braille display system which is modular and therefore, quickly and easily assembled or repaired.
Still another object of the present invention is to provide a Braille display system which can present text and limited graphics, normally displayed on a computer display terminal or CRT, to a visually impaired person.
Still another object of the present invention is to provide a Braille display system that has a tactile surface with no holes, gaps or voids, and provides a continuous uninterrupted tactile reading surface for the user eliminating any interference with reading of Braille characters and preventing environmental damage to the underlying Braille display hardware.
Accordingly, the present invention relates to a refreshable Braille display; comprising a plurality of Braille dots that extend and retract, arranged in Braille characters such that the Braille dots are operable as a personal computer monitor to allow a blind person to discern the information displayed thereon by reading the Braille characters. At least one microelectromechanical device operably connects to the Braille dots such that the Braille dots retract and extend based upon the operation of the microelectromechanical device. The Braille character comprises six or eight Braille dots. Multiple Braille characters are arranged in functionally independent modules of rows and columns. The microelectromechanical device operates electrostatically or comprises shape memory alloy material. The microelectromechanical device will either directly move a pin or directly form the individual Braille dots, or it will pneumatically move a pin or directly form a Braille dot.
In another aspect, the present invention relates to a refreshable Braille display; comprising a housing; a plurality of Braille dots arranged in Braille characters mounted in the housing; at least one microelectromechanical device operably attached to each Braille dot; a compressor which provides air pressure to the microelectromechanical devices; a microcontroller mounted in the housing and programmed to directly control the operation of the microelectromechanical devices to extend and retract the Braille dots; a personal computer programmed with Braille translation software and connected to the microcontroller. The information and data from the personal computer is translated and transferred to the microcontroller. The microcontroller operates the microelectromechanical device in response thereto which extends and retracts the Braille dots allowing a blind person to discern the information displayed thereon by reading the Braille characters formed by the extended Braille dots.
In yet another aspect, the present invention relates to a refreshable Braille display system, comprising a housing; at least one module mounted in the housing, and a top surface sealed to the housing and the modules. The top surface is an elastomeric material and is selectively deformable. At least one microelectromechanical device is mounted in the module such that the microelectromechanical device selectively deforms the top surface by forming dimples therein. The dimples function as Braille dots and form Braille characters. The microelectromechanical device selectively flattens the dimple thereby removing the Braille dot and thereby changing or removing the Braille character. The Braille dots and the Braille characters form a Braille display. A module microcontroller controls the microelectromechanical device. A microcontroller coordinates each individual module microcontroller and communicates with the computer. A personal computer programmed with Braille translation software connects to the microcontroller such that information and data from the personal computer is translated and transferred to the microcontroller. The microcontroller or the module microcontrollers operate the microelectromechanical devices in response thereto which forms the Braille dots allowing a blind person to discern the information displayed thereon by reading the Braille characters formed by the Braille dots.